Electric incandescent lamps



1966 A. s. VAUSE ET AL 3,286,118

ELECTRIC INCANDESCENT LAMPS Filed June 28, 1963 United States Patent3,286,118 ELECTRIC INCANDESCENT'LAMRS. I Arthur S. Vause, Rugby, andJohn W. T. Wrrght,-'Le1- cester, England, assignors to AssociatedElectrical Industries Limited, Londo'n,E'ngland, a British compan FiledJune 28, 1963, Ser. No. 291,319 1 Claims priority, application GreatBritain, July 6, 1962,

26,0 5/62 5 Claims. (Cl. 313-318) This invention relates to electricincandescent lamps. Heretofore incandescent lamps have generallycomprised a filament assembly sealed into one end of an evacuated, orgas-filled glass bulb, the seal being covered with a protective capwhich serves to support the lamp in a holder and by which the electricalconnections to the filament are made.

However, incandescent lamps known as architectural and festoon lampscomprise a tubular glass envelope having a filament extending axially.therein, the electrical connections to the filament passing throughseals located at the ends of the envelope.

In accordance with the present invention, an electric incandescent lamphas a sealed envelope comprising two preformed members of generallyrectangular configuration and of light transmitting vitreous materialsealed together along their adjacent flanged peripheries with at leastone filament supported, within the envelope with each electricalconnection thereto extending in sealed relation through opposed edges ofthe joint. between the members to the exterior of the envelope.

The two pre-formed members are so shaped that when they are sealedtogether the resulting envelope is in the form of a hollow panel whichis suitable for mounting directly on either a wall or ceiling. Eachmember may be in the form of a trough provided at its mouth with anoutwardly turned flat rim, and in order to form the envelope the membersare assembled in face-to-fa'ce relation with their rims injuxtaposition, the rims being then sealed together along theirperiphery.

A plurality of filaments may be provided within the envelope, and, ifdesired, separate electrical connections may be made to each filament sothat by energising one or more of the filaments the light output of thelamp may be varied. The electrical connections which support thefilament or filaments within the envelope extend through the sealedjoint between the two members to the exterior of the envelope, and bychoosing for the conductor providing the connections to the filament ametal which has a temperature coefficient of expansion compatible withthat of the vitreous material of which the members are formed, the riskof the seal breaking down when heated is reduced.

It is envisaged that the lamp will most often be mounted with thefilament or filaments substantially horizontal by providing a suitablefitting which surrounds the envelope and to which the lamp is securedalong at least part of its periphery. The fitting will be generally ofelectrically insulating material, but having contacts provided whichengage with the electrical connections which extend through the jointbetween the members forming the envelope. Conventional electricincandescent lamps are usually operated with the support cap uppermost,and in this way the seal at the end of the glass bulb and the protectivecap are at the hottest portion of the lamp; but an incandescent lamp inaccordance with the present invention is conveniently secured to thefitting along at least part of its outer periphery and the seal betweenthe tWo vitreous members can be arranged to be the coolest part of thelamp.

Each of the electrical connections to the filament which extend to theexterior of the envelope may be terminated in a looped portion whichserves as a terminal member by which the electrical supply is applied tothe filament. The looped portion may follow the contour of the envelopein the vicinity of the seal through which the connection emerges fromthe envelope.

In an alternative embodiment of the invention, each of theelectricalconnec-tions which extend to the exterior of the envelope issecured to one of a plurality of clips of conducting resilient materialwhich are positioned on the flanged periphery of the envelope.

In order that the invention may be more readily understood, it will nowbe described with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of one embodiment of the invention,

FIG. 2 is a perspective view of a further embodiment of the invention,and

FIG. 3 is a perspective view of an alternative embodiment of theinvention. Reference numerals 1 and 2 denote pre-formed members of lighttransmitting vitreous material which are of generally rectangularconfiguration. The vitreous material may be, for example, a glass havingsuitable physical characteristics, fused silica, or a translucentsintered ceramic, and the members are formed by casting techniques or bydistorting vitreous ribbon or sheet which has been raised to atemperature at which it is pliable. Each memher is in the form of atrough having at its month an outwardly turned flat rim 3. To improvethe operation or appearance of the lamp, the inner and outer surfaces ofthe members may be provided with a diffusing, fully reflec'ting, orselective reflecting coating. If it is desired to control the directionof light emission from the lamp, one or both of the pre-formed membersmay be made with prismatic or other flutes to retract light emitted intothe desired directions. The surface of one or both of the members may beprovided with a decorative design, if required.

The envelope is formed by positioning the two members together inface-to-face relation with their rims in contact and sealing themtogether along the periphery of the rims. At least one filament 4 islocated within the envelope with the electrical connections theretoextending in sealed relation through opposed edges of the joint betweenthe members to the exterior of the envelope. In the embodiment shown inFIG. 1, one filament is provided, and in the embodiments of FIGS. 2 and3, four and three filaments, respectively, are employed.

The lamp is assembled by sandwiching one or more filaments and theirconnections between the adjacent rims of the two members and applyingheat and pressure to the adjacent flanged surfaces of the members,thereby sealing the assembly. Exhausting and/or gasfilling of theenvelope is carried out by means of a tube extending through an openingin the periphery of one of the members, the tube being subsequentlysealed off.

In the embodiments of the invention shown in FIGS. 1 and 2, theelectrical connections to the filaments or each filament extend insealed relation through the joint and are terminated by contact strips 5of resilient material which are located on the flanged periphery 3 ofthe envelope, and one of the electrical connections to the filament isconnected to each strip. Two or more of the contact strips may beconnected together so that the filaments are in series/parallel relationin order that one or more of the filaments may be energized as required.

FIG. 3 shows an embodiment of the invention in which a portion of eachelectrical connection to the filament which extends to the exterior ofthe envelope is terminated in a looped portion 6 which serves as aterminal the contour thereof.

member by which the electrical supply may be applied to the filament.The looped portion may follow the contour of the envelope in thevicinity of the seal through which the connection emenges from theenvelope.

When the filament of the lamp is of low power rating, the connections oreach electrical connection which extends through the wall of theenvelope is conveniently in the form of a thin wire which can easily beflattened into engagement with the wall of the envelope, so as to followIf, however, the power rating of the filaments demands the electricalconnections to be of thicker dimensions the resilience of the materialfrom which the conductor is formed may make it impossible for thelooped-portion to be flattened completely into engagement with the wallof the envelope, in which case at least part of the looped portion willbe spaced apart by a small distance from the wall of the envelope.

The end of the looped portion 6 of each connection is returned into thejoint between the two pre-formed members on the same side of theenvelope and is hermetically sealed therein. The two ends of the loopare thus rigidly secured in the joint between the two preformed members,and the loop serves as a terminal member. If desired, the loop extendingbetween the two rigidly secured ends of the connection may be flatteneddown on to the wall of the envelope in the vicinity of the sealed endsof the connection to take up the contour of the wall. The singlefilament comprises three sections and the connections 4a betweenadjacent sections are sealed in the joint between the members.

What we claim is:

1. An electric incandescent lamp comprising a sealed light transmittingenvelope composed of two trough shaped members with rims sealed togetherin opposed relation with the rims in contact, at least one filamentwithin the envelope and electrical connections from respective ends ofeach filament extending in sealed relation between said rims to theexterior of the envelope with the end of each connection remote from thefilament sealed between said rims to provide a looped terminal memberfor the filament.

2. An electric incandescent lamp comprising a sealed light transmittingenvelope composed of two trough shaped members with outwardly flangedrims sealed together in opposed relation with the rims in contact, atleast one filament within theenvelope and electrical connections fromrespective ends of each filament extending in sealed relation betweensaid flanged rims to the exterior of the envelope with the end of eachconnection remote from the filament sealed between said flanged rims toprovide a loop terminal member for the filament.

3. An erlectricin-candescent lamp comprising a sealed light transmittingenvelope composed of two trough shaped members with outwardly flangedrims sealed together in opposed relation with the rims in contact, atleast one filament within the envelope, and electrical connections fromrespective ends of each filament extending in sealed relation betweensaid flanged rims to the exterior of the envelope with the end of eachconnection remote from the filament sealed between said flanged rimsadjacent the other portion of the connection extending between saidflanged rims to provide a looped terminal member for the filament.

4. An electric incandescent lamp comprising a sealed light transmittingenvelope composed of two generally rectangular trough shaped memberswith rims sealed together in opposed relation with the rims in contact,at least one filament within the envelope arranged with its axisgenerally normal to the longitudinal axis of the envelope and electricalconnections from respective ends of each filament extending in sealedrelation between the rims along the longer sides of the envelope to theexterior thereof with the end of each connection remote from thefilament sealed between said rims to provide a looped terminal memberforthe filament.

5. An electric incandescent lamp as claimed in claim 4, in which therims are flanged and a single filament divided between its ends to format least two sections is provided with the'sections arranged normal tothe longitudinal axis of the envelope and the connections betweenadjacent sections of the envelope located between said flanged rims.

References Cited by the Examiner UNITED STATES PATENTS DAVID J. GALVIN,Primary Examiner.

1. AN ELECTRIC INCANDESCENT LAMP COMPRISING A SEALED LIGHT TRANSMITTINGEVELOPE COMPOSED OF TWO TROUGH SHAPED MEMBERS WITH RIMS SEALED TOGETHERIN OPPOSED RELATION WITH THE RIMS IN CONTACT, AT LEAST ONE FILAMENTWITHIN THE ENVELOPE AND ELECTRICAL CONNECTIONS FROM RESPECTIVE ENDS OFEACH FILAMENT EXTENDING IN SEALED RELA-